Current Molecular Pharmacology - Volume 7, Issue 1, 2014

Breast carcinoma is currently considered as a group of diseases, differing not only in histopathologic phenotype, as indicated by histologic type and grade, but also in their protein, genetic and epigenetic molecular profile. The standard of care indicates that the core information for patient management includes data on Estrogen Receptor (ER), Progesterone Receptor (PgR) and Human Epidermal Growth Factor Receptor 2 (HER2), while there is an emerging role for the proliferation marker Ki67. These indices can be provided even in low resource settings and are indispensable for prognostication and therapeutic patient management. With the progress in molecular and translational research, there is a growing body of information on the molecular subtypes of breast carcinoma and their significance, and multigene signature assays are used to dictate prognosis and guide therapeutics in high resource settings. In addition, several cellular pathways involved in tumor growth and spread are dissected and targeted in clinical trials. Among these are the p53, RB, PI3K/Akt/mTOR and Ras/MAPK pathways, alterations associated with genetic instability and epigenetic alterations including histone methylation and acetylation, DNA methylation and microRNAs expression. The tumor immune microenvironment, including the tumor infiltrating lymphocytes (TILs) is attracting significant research interest. This review summarizes the mechanisms of function of the above factors in breast tumorigenesis with emphasis on their prognostic and predictive value and their use as therapeutic targets.

Lung malignancy is a leading cause of cancer related morbidity and mortality worldwide. The majority (85%) of cases are histologically proven non-small cell lung carcinomas (NSCLC). More than 55% of lung carcinomas harbor at least one genetic alteration, most of them being histologic subtype specific. This review summarizes the progress in personalized care of lung cancer by reviewing the literature on EGFR, ALK and KRAS molecular alterations, currently used in clinical practice, to direct the decision making process for lung cancer therapy. In addition, we will discuss some recently characterized molecular alterations whose targeting is being tested in clinical trials and holds promise for future therapeutic targeting. The role of minimally invasive procedures in lung cancer diagnosis and staging is also discussed as these techniques now play a central role in lung cancer management by providing the bulk of material for modern molecular diagnostics.

Metastatic melanoma has a poor prognosis and until today most therapeutic approaches are ineffective. Advances in molecular pathology and genome analysis technologies have led to the identification of genetic events and immune regulatory checkpoints that provide novel targets for pharmaceutical intervention in melanoma. Development of selective mitogen-activated kinase (MAPK) pathway inhibitors was the first major achievement coming from genetic studies that identified a constitutively active MAP kinase pathway and BRAF activating mutations in melanoma. At the same time, the manipulation of immune system checkpoints through monoclonal antibodies changed clinical practice and led to further improvement of patient outcomes. In an effort to further develop melanoma targeted therapies that depend on the genetic profile of a given patient, high-throughput genome wide approaches (next-generation sequencing [NGS], gene arrays, etc) have been employed for the characterization of genetic alterations in the patient’s tumor. In the near future, the combined information from the genetic and immune background of an individual will provide the basis for a personalized, highly targeted approach in the treatment of melanoma.

Discovery of novel cancer chemotherapeutics focuses on screening and identifying compounds that can target ‘cancer-specific’ biological processes while causing minimal toxicity to non-tumor cells. Alternatively, model organisms with highly conserved cancer-related cellular processes relative to human cells may offer new opportunities for anticancer drug discovery when combined with chemical screening. Some organisms used for chemotherapeutic discovery include yeast, Drosophila, and zebrafish which are similar in important ways relevant to cancer study but offer distinct advantages as well. Here, we describe these model attributes and the rationale for using them in cancer drug screening research.

Treatment of chemical dependence (“addiction”) requires an understanding of its effects on the brain. To guide research in the area of chemical dependence, several foundational theories have been developed. These include the incentive salience, receptor down-regulation, opponent process, and psychomotor stimulant theories. These have been important both in summarizing and in guiding investigations. However, the extant theories do not provide a single unified framework nor have they yielded all of the guidance necessary for effective chemical dependence treatment. The present paper summarizes and then integrates these theories and suggests some implications for the treatment followed by this integration.

The CB2 cannabinoid receptor is a promising therapeutic target for the treatment of inflammatory diseases, neuropathic pain, liver diseases, cancer and cardiovascular diseases. Obtaining detailed information on the internalization and trafficking of the human CB2 receptor in response to agonist will have a significant impact on drug discovery. Visualization and quantitative detection of EGFP-tagged CB2 receptor showed that, upon WIN55,212-2 stimulation, the CB2 receptor was rapidly internalized in a dose- and time-dependent manner from the cell membrane into the cytoplasm. Pretreatment with hypertonic sucrose, MDC clathrin inhibitor, or siRNA-mediated knock-down of clathrin heavy chain led to significant inhibition of agonist-induced CB2 internalization. Using the RNA interference method, we showed that knockdown of β-arrestin2 expression significantly impaired receptor internalisation. Further investigation demonstrated that the internalized CB2 receptors were co-localized with the early endosome probe and were recycled to the cell surface after the removal of agonist, but treatment with specific cell-permeable proteasome inhibitor MG132 a inhibited the recycling of internalized CB2 receptor, suggesting that the proteasome-mediated degradation pathway may be involved in CB2 internalization. Moreover, the single residue Ser352 and residue cluster S335S336T338T340 at the C-terminal tail are shown to be essential for receptor phosphorylation and β-arrestin2 association. These data provide new insights into the mechanisms regulating agonist-mediated internalization and trafficking of the human CB2 receptor.